English

A notion of minor-based matroid connectivity

Combinatorics 2018-07-24 v2

Abstract

For a matroid NN, a matroid MM is NN-connected if every two elements of MM are in an NN-minor together. Thus a matroid is connected if and only if it is U1,2U_{1,2}-connected. This paper proves that U1,2U_{1,2} is the only connected matroid NN such that if MM is NN-connected with E(M)>E(N)|E(M)| > |E(N)|, then M\eM \backslash e or M/eM / e is NN-connected for all elements ee. Moreover, we show that U1,2U_{1,2} and M(W2)M(\mathcal{W}_2) are the only connected matroids NN such that, whenever a matroid has an NN-minor using {e,f}\{e,f\} and an NN-minor using {f,g}\{f,g\}, it also has an NN-minor using {e,g}\{e,g\}. Finally, we show that MM is U0,1U1,1U_{0,1} \oplus U_{1,1}-connected if and only if every clonal class of MM is trivial.

Keywords

Cite

@article{arxiv.1705.03418,
  title  = {A notion of minor-based matroid connectivity},
  author = {Zachary Gershkoff and James Oxley},
  journal= {arXiv preprint arXiv:1705.03418},
  year   = {2018}
}

Comments

13 pages

R2 v1 2026-06-22T19:41:56.263Z